QUESTION: So if Liberal Party doesn’t have a position on nuclear power are you concerned that Ms Bishop is advocating that this should be considered? TONY ABBOTT: Well, I’ll get Julie to say a few words in a sec. But look, I’m perfectly happy to see a debate and I’m perfectly happy to see other countries do what’s in their best national interests. But we have no policy for the establishment of nuclear power in this country. It’s my understanding that there are no proposals for the establishment of nuclear power in this country. It’s my further understanding that the generation of electricity by that method would be much more expensive in this country than generation by coal or by gas, and there’s really no point going to a different technology if it’s going to drastically raise the price of power. Julie.
And they're opposed to it on the grounds of it being too expensive compared to coal and gas.
The ALP doesn't have an official policy platform on it by the looks of it, but there are a few sympathetic souls. I suspect that their policy is similar to the draft Energy White Paper delivered in December 2011 (pages 223-224):
The government has chosen not to permit the use of nuclear energy in Australia and the use of nuclear technology for power generation is expressly prohibited under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999. At the Australian Government level, advice on this issue was most recently commissioned in 2006. There has, at different times, been passionate debate on this issue.
The Gillard Government unambiguously does not support the use of nuclear energy in Australia, noting that at present there is no necessary social consensus over this technology nor is there currently a compelling economic case, even taking into account the need to reduce our national emissions. Australia will invest heavily in renewable and other clean energy technologies such as carbon capture and storage as preferred alternatives to conventional high‐emissions generation.
From a little bit further on:
The best case supporting future consideration of nuclear power would be the failure to commercialise new low‐emissions baseload energy or energy storage technologies within the timeframe that economic analysis suggests is necessary to meet long‐term global and national emissions reduction objectives (from 2025 onwards).
Realistically, such a decision would also have to attract broad community consensus. Australian history suggests that this would require bipartisan political support and, in the wake of the recent tragedy in Fukushima, the prospect of new safer nuclear generation technologies and waste disposal options.
That last quotes seems to indicate what the problem is. No-one will move because the only strong voice on the issue of nuclear power in Australia is the Greens, who pretty much oppose it on purely ideological grounds.